I do something similar, albeit a bit leakier. I have all my money coming in to one nexus account, and then I have weekly/biweekly/monthly outflows of everything (bills, stock investments, transfers to 3x different banks, mortgage). I keep that account with a bunch of buffer, but ignore all my other accounts. Each month I keep that main account 'floating' is another month where all those other accounts are growing. If I ever dip too low, I can supplement with one of my other accounts.

It's not a great solution, but it's the one that I've stuck with best.